Hematoxylin and eosin stained samples from the wild-type (A) and Acancmd/+ mice (B & C), toluidine blue-stained sample from a heterozygote (D), and Alcian blue-stained samples from the wild-type (E) and heterozygotes (F) are shown. Spines of heterozygotes show protrusion of discs [Th3~4 (B) and Th4~5 (C)] or marked herniation at C4~5 (D). Note disappearance of apophyseal cartilage and deformation of vertebral bodies in heterozygotes (B-D) while the spines of the wild type show no remarkable changes (A). Note staining around chondrocytes in the cartilage from heterozygotes (F) while diffuse staining patterns are observed in that from the wild type (E). Magnification: A-C: x10; D: X25; E & F: x125